Methylcobalamin (vitamin B12)

Generic name: methylcobalamin (vitamin B12) oral/injection [ METH-il-koe-BAL-a-min ]
Brand names: Methyl B-12, Vitamin B12 Methylcobalamin
Dosage forms: injectable solution (1 mg/mL; 10 mg/mL; 5 mg/mL), oral capsule (2000 mcg), oral lozenge (1 mg; 500 mcg), oral tablet, disintegrating (1 mg), sublingual tablet (5000 mcg)
Drug class: Vitamins

Medically reviewed by Drugs.com on Sep 28, 2022. Written by Cerner Multum.

What is methylcobalamin?

Methylcobalamin is used to treat vitamin B12 deficiency. Vitamin B12 is important for the brain and nerves, and for the production of red blood cells.

Methylcobalamin is sometimes used in people with pernicious anemia, diabetes, and other conditions.

Methylcobalamin may also be used for purposes not listed in this medication guide.

Warnings

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use methylcobalamin if you are allergic to vitamin B12 or cobalt.

Tell your doctor if you have ever had:

Leber's disease or other form of optic nerve damage;
an iron or folic acid deficiency; or
low levels of potassium in your blood.

Tell your doctor if you are pregnant or breastfeeding.

Do not give methylcobalamin to a child without medical advice.

How should I use methylcobalamin?

Use exactly as directed on the label, or as prescribed by your doctor.

Methylcobalamin oral is taken by mouth.

Methylcobalamin injection is injected into a muscle, usually 1 to 3 times per week. A healthcare provider can teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Do not swallow a lozenge, disintegrating tablet, or sublingual tablet whole. Allow it to dissolve in your mouth without chewing. The sublingual tablet should be placed under your tongue.

Your dose needs may change if you become pregnant, if you breastfeed, or if you eat a vegetarian diet. Tell your doctor about any changes in your diet or medical condition.

For more information you may also consult the Office of Dietary Supplements of the National Institutes of Health, or the U.S. Department of Agriculture (USDA) Dietary Reference Intakes (formerly "Recommended Daily Allowances") listings for more information.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking methylcobalamin?

Avoid drinking large amounts of alcohol. Heavy drinking can make it harder for your body to absorb methylcobalamin.

Methylcobalamin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Common side effects of methylcobalamin may include:

nausea, vomiting, diarrhea;
loss of appetite; or
headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect methylcobalamin?

Tell your doctor about all your other medicines, especially:

chloramphenicol;
colchicine
antibiotic medicine;
oral diabetes medicine that contains metformin; or
medicines that reduce stomach acid, such as cimetidine, omeprazole, lansoprazole, Nexium, Prevacid, Prilosec, Zantac, and others.

This list is not complete. Other drugs may affect methylcobalamin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

More about methylcobalamin

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer